399684426436 has 81 divisors (see below), whose sum is σ = 749779846767. Its totient is φ = 186399617040.

The previous prime is 399684426391. The next prime is 399684426437. The reversal of 399684426436 is 634624486993.

It is a happy number.

The square root of 399684426436 is 632206.

It is a perfect power (a square), and thus also a powerful number.

It is not an unprimeable number, because it can be changed into a prime (399684426437) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 3051026091 + ... + 3051026221.

Almost surely, 2^399684426436 is an apocalyptic number.

399684426436 is the 632206-th square number.

It is an amenable number.

399684426436 is a deficient number, since it is larger than the sum of its proper divisors (350095420331).

399684426436 is a wasteful number, since it uses less digits than its factorization.

399684426436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 558 (or 279 counting only the distinct ones).

The product of its digits is 161243136, while the sum is 64.

Multiplying 399684426436 by its sum of digits (64), we get a square (25579803291904 = 5057648²).

The spelling of 399684426436 in words is "three hundred ninety-nine billion, six hundred eighty-four million, four hundred twenty-six thousand, four hundred thirty-six".